Vented fastener

Abstract

A fastener for venting gas around the shank of the fastener. The present invention includes various embodiments for venting gases such as combustion gases that seep from a head gasket of an internal combustion engine to the area around the shank of a cylinder head bolt, as one example. The various vent paths include vent paths directly through the bolt, past the bearing surface of the bolted member, or past a washer between the fastener and the bolted member. These vent paths prevent gases from building up in the chamber between the fastener shank and the clearance hole of the bolted member.

What is claimed is:  
     
       1. An apparatus comprising: 
       an internal combustion engine including a cylinder head defining a hole; and  
       a fastener including a head and a shank, the head having a bearing surface defining at least one channel across a portion of the bearing surface;  
       wherein said fastener is received within the hole and said bearing surface is in contact with said cylinder head when said fastener threadably couples said cylinder head to said engine, the hole and the shank defining a chamber therebetween, and said channel venting gas from within the chamber;  
       wherein said cylinder head defines an intake passage for said engine, intake air for said engine flowing through said intake passage, the head of said fastener being exposed to the flowing intake air, said channel venting gas from within the chamber to the intake passage; and  
       which further comprises a block for said engine and a gasket partially sealing portions of said cylinder head from portions of said block, whereby combustion gas flows into the chamber, though said channel, and out to said intake passage;  
       wherein said fastener head includes four equally spaced channels in the bearing surface.  
     
     
       2. An apparatus comprising: 
       an internal combustion engine including a cylinder head defining a hole; and  
       a fastener including a head and a shank, the head having a bearing surface defining at least one channel across a portion of the bearing surface;  
       wherein said fastener is received within the hole and said bearing surface is in contact with said cylinder head when said fastener threadably couples said cylinder head to said engine, the hole and the shank defining a chamber therebetween, and said channel venting gas from within the chamber;  
       wherein said fastener head includes a plurality of channels.  
     
     
       3. The apparatus of  claim 2  wherein said channels are equally spaced in the bearing surface. 
     
     
       4. The apparatus of  claim 3  wherein there are four channels. 
     
     
       5. An apparatus comprising: 
       a first member defining a first hole and a first bearing surface proximate the perimeter of said first hole;  
       a second member defining a second threaded hole;  
       a cylindrical shank with two ends and including a threaded portion, said shank being slidable through said first hole, said threaded portion being threadably engageable with the second threaded hole; and  
       a head attached to one end of said shank, said head including a second bearing surface extending from a point near said shank toward the perimeter of said head, said second bearing surface being arranged and constructed to contact said first bearing surface, said first bearing surface including at least one channel;  
       wherein said second bearing surface contacts said first bearing surface when said shank passes through said first hole and threadably couples to said second hole, said channel providing fluid communication from the exterior of said head to an annular volume formed between said shank and said first hole;  
       wherein said first hole includes a centerline, and said first bearing surface of said first member includes a channel extending in a direction radially outward from said centerline;  
       wherein said first bearing surface includes a plurality of radially extending channels.  
     
     
       6. An apparatus comprising: 
       a first member defining a first hole and a first bearing surface proximate the perimeter of said first hole;  
       a second member defining a second threaded hole;  
       a cylindrical shank with two ends and including a threaded portion, said shank being slidable through said first hole, said threaded portion being threadably engageable with the second threaded hole; and  
       a head attached to one end of said shank, said head including a second bearing surface extending from a point near said shank toward the perimeter of said head, said second bearing surface being arranged and constructed to contact said first bearing surface, said second bearing surface including at least one channel;  
       wherein said second bearing surface contacts said first bearing surface when said shank passes through said first hole and threadably couples to said second hole, said channel providing fluid communication from the exterior of said head to an annular volume formed between said shank and said first hole;  
       wherein said shank includes a centerline, and said second bearing surface of said head includes a channel extending in a direction radially outward from said centerline;  
       wherein said second bearing surface includes a plurality of radially extending channels.  
     
     
       7. The apparatus of  claim 6  wherein said cylindrical shank and said head comprise a bolt. 
     
     
       8. The apparatus of  claim 6  wherein said first member is a cylinder head for an internal combustion engine, said second member is a block for an internal combustion engine, and said channel vents combustion gas from between said cylinder head and said block. 
     
     
       9. The apparatus of  claim 6  wherein said first member is a cylinder head for an internal combustion engine, and said channel vents combustion gas leaking into the annular volume. 
     
     
       10. A method for coupling a cylinder head to an internal combustion engine, comprising: 
       providing a fastener, a first member, and an internal combustion engine including an intake passage;  
       coupling the first member to the engine with the fastener;  
       forming a chamber between the fastener and the first member by said coupling;  
       leaking combustion gas from the engine into the chamber; and  
       venting the combustion gas from the chamber by establishing fluid communication from the chamber to the intake passage.